1. Field Of The Invention
This invention relates to web handling equipment and methods, and more particularly to web splicers and methods.
2. Prior Art
Web splicing is employed in many continuous processes for introducing new webs to the processes as old webs expire. A goal or object of web splicing is to introduce a new web without interruption of the process. Another object is to introduce the fresh web without waste of the expiring web, or the leading end (lead) of the new web.
Webs are stored and fed from spools, comprising continuous paper or similar material spirally wound on cores. In the past, web splicers have generally spliced a fresh web onto an expiring web before the expiring web has separated from its core. While this method of splicing is wasteful of the tail of expiring webs, the method has generally been considered necessary to assure no loss of tension in the web. A loose tail means a loss of tension in the tail. Problems with past splicers have included waste as described, failure to maintain sidelay of a fresh web consistent with that of an expiring web, lack of reliability, and complexity.
A notable exception to the described splicers was a predecessor of this invention. This predecessor is illustrated schematically in FIG. 1 of the accompanying drawing. A hammer 10 and anvil 12 of the predecessor were adapted to seize the tail of an expiring web 14. A pair of rollers 16, 18 upstream of the hammer and anvil were adapted to press the tail and the lead 20 of a fresh web together, to adhere the tail to an adhesive strip 22 manually pre-placed on the lead. Loss of tension in the tail as it separated from the core caused an upper drop roller 24 to rise. The rise tripped a switch, causing the hammer 10 to press the tail to the adhesive 22 against the anvil 12, stopping the expiring web 14. The stopping caused extreme movement of a dancer in a web tensioning carriage, tripping another switch and pressing the roller 18 against the fixed idler 16. Simultaneously the hammer 10 released, and the expiring web 14 and the lead 20 moved forward. The dancer fell, tripping the second switch and releasing roller 18.